Previously this applicant applied for Utility Model to the Korean Patent Office and it was published by the Notice No. 85-850 of Public Gazette No. 711. It had a cooling mechanism almost identical to the present invention. It, however, had the following several defective structures: The process of charging refrigerant gas into gas chamber and closing it was difficult; due to the flush bottomline of the gas chamber, discharging refrigerant gas by removing the cap for the outlet opening at the top of the can was not easy, consequently requiring tipping of the can to expedite the same process; another structural defect was the ring with the functions of starting the discharge process of refrigerant gas because when it was pressurized inadvertently it touched off accidental discharge of refrigerant gas.